Flying high

The unveiling of Mumbai’s swanky new Terminal 2 (T2) at Chhatrapati Shivaji International Airport (CSIA) has given the city a new landmark to be proud of and marks the transition of airport construction to a new era.

The aim was to create one of the world’s best airports, and today, the gigantic glass structure – T2 at CSIA – commands attention from all passer-bys. Inaugurated by Dr Manmohan Singh, Prime Minister of India, the four storied terminal spreads across 4.4 mn sq ft and sets a new global benchmark in the development of airport infrastructure.

Concept plan

The construction site of the new T2 building was located in close proximity to the existing terminal which had to remain fully operational during construction. This inspired the elongated X-shape plan of the terminal that can both mold around existing structures and incorporate modular designs to accommodate rapid and phased construction.

Designed by New York-based, SOM, T2 has been developed to handle a capacity of close to 40 million passengers annually. Laura Ettelman, Director, Skidmore, Owings & Merrill says, “Our client, GV Sanjay Reddy stated his goals very succinctly: The terminal must embody the heritage of India and the spirit of Mumbai. We used our full capabilities, from architecture to structural engineering, to create an airport for Mumbai that could inspire and endure.”

Peacock inspired

The terminal’s roof has been designed driving inspiration from the white peacock and measures approximately 11 acre in area making it one of the longest-span building structures in India. Ettelman adds, “One of the biggest construction achievements of the terminal is the steel truss terminal roof. Concrete is the preferred structural system in India, but the long-span terminal roof required the use of steel. In order to enhance constructability, the structure is hidden within a decorative cladding.” The roof is a two-way long-span steel truss structure supported by 30 unbraced feature columns spaced 64 m x 34 m. The spacing at large intervals means that each column carries a load of about 2,000 tonne. The engineers designed each column of high-grade steel plates in a cruciform shape to deal with the large wind or earthquake induced bending moment and sway. Equipment such as giant cranes with 500 MT capacities were deployed to erect the steel structures. Thirty diamond-shaped pods were used to enhance the design of the mega roof and each pod comprises 4,200-4,500 steel elements, weighing 250 tonne. These elements were pre-fabricated and condensed to nearly 150 components before delivery. Assembly of each pod required over 10,000 bolts and 80 men.

Going vertical

Each column measures 4.2 m x 3.4 m rising from the ground to a height of 40 m. The mega structure of the feature columns are created with concrete encased steel. In this segment, the steel has a cruciform plan of 2.3 m x 2.3 m and the concrete encasing is 2.7 m in diameter. The exterior feature columns are rendered in panels of glass fibre reinforced concrete (GFRC) and appear identical to the interior ceiling and columns that are rendered in panels of glass fibre reinforced gypsum (GFRG). The ceilings in both the interior of the check-in hall and international security screening area and the exterior space which covers the departures curbs are rendered in GFRC and GFRG respectively and are 15 m in height.

Technological marvel

Larsen & Toubro, the contractors of the project, made use of a number of new technologies for fast and precise project execution , many of which for the first time in India. Hydraulic concrete crushing machines were used for demolition which involves a state-of-the-art method of dismantling existing structures. It is highly efficient resulting in 35 per cent savings in cost. Rubbelisation was the answer for apron construction as the existing pavement had to be removed and a new one constructed in its place. To avoid the massive logistical challenge of breaking, excavating and removing the waste material in an already congested and fully functioning airport, advanced machines rubblising equipment were sourced which reduced the volume to be removed, reduced equipment resources and saved some 75,000 truck trips. Carbon reinforced fiber technology was employed to strengthen the existing bridges especially the one under the main new runway that had to take new-age aircraft such as the A-380 and withstand the pressure of a landing or take-off every 3 minutes. Due to the space constraint, a unique erection methodology called was adopted for the Head House structural steel works, using special launching mechanism. The entire engineering was carried out with 3D detailing and Building Information Modeling (BIM).

Wooden ceiling

Apart from this, the wood ceiling in the interiors of the terminal is actually metal, printed with a very realistic facsimile of wood. Lopa Desai, Local Partner, durlum GmbH says, “The ceiling of T2 is primarily constructed from metal panels with a powder coat finish. The specification for individual areas was well thought out and demanded to be made from the latest manufacturing techniques. Layout of the ceiling is tailor made to suit the unique geometry of the terminal building.”

She adds, “The ceiling panels are made from Galvanised Metal Sheet (GMS) which are perforated with small circular holes to allow sound to be transmitted through the panel. The surface of the panels were finished in an imitation woodgrain finish that was applied by plotting (printing) using advanced technology. The panels then went through a process whereby transparent powder coating was applied for protection. Finally, an acoustic fleece is factory bonded on the back of the panels for sound absorption.”

Illuminating spaces

At the terminal’s entrance, the head house roof comprises 28 major skylights and 244 minor skylights – the largest ever built in Asia. This entire layout of 272 skylights spans over 30,000 sq m bringing in natural light into the terminal. Also, nearly 5,698 ‘dichroic lenses’ have been used within the roof to give the closest possible look of the peacock feathers on the floor. Small disks of colourful glass recessed within the canopy’s coffers speckle the check-in hall with light, with its constellation of colours as a reference to India’s national bird – the peacock.

Artificial lighting in the gate lounges are provided by chandeliers and curtain wall that is approximately 2 km in length. The ceiling of departure lounges are embellished with around 1,000 hand-crafted lotus chandeliers designed by Architect Sandeep Khosla. The chandeliers representing three stages of blooming of a lotus have been procured from Czech Republic and the Diya and Phulkari lights from Dubai. Designers Abu Jani and Sandeep Khosla say, “The materials for the lights range from extruded aluminum, LED lights to custom glass. Using the latest computer technology and manufacturing techniques, these installations are economical, yet exude the richness.” A total of 71,264 light fixtures with 85 variants have been installed at the venue. Also, a 15 m tall cable stayed glass wall – the longest in the world – opens to the soaring space of the check-in hall with the transparent facade.

Added facilities

The terminal also features 188 + 20 check-in counters underneath the mega roof. It also includes 41 travellators, 47 escalators and 73 elevators. Antony Parokaran CEO- Schindler India says, “For terminal 2 at Chhatrapati Shivaji International Airport, Schindler has installed 113 units, elevators- 52 units, escalators-39 units and moving walks- 22 units.” He adds, “The elevators installed in the project include PMS gearless machines that reduce power consumption. The escalators are equipped with ECOLINE power management, it enables to define whether the escalator should run at full speed during peak times and automatically slow down or even stop when there are no passengers.”

The project also comprises a unique baggage handling system equipped with India’s largest world-class energy efficient automated LS-4000E tilt tray sorters. The system is designed to handle 9,600 bags per hour with an expandable capacity of up to 10,800 bags per hour. T2 has India’s largest airport escalator measuring 11.6 m in height serving to the sixth to 10th level of the multi-level car park.

Jaya He

The most talked about section of the airport is the 3 km long multi-storey ‘Art Wall’ titled – Jaya He. Illuminated by skylights, it is India’s largest public art programme that has over 7,000 pieces of artwork and artifacts from across diverse regions across the country.

Green footprint

T2 is a LEED Gold certified project that is highly energy and water efficient. Sewage recycling, water recycling and rainwater harvesting technologies will contribute to a 20 per cent reduction in water use, over and above the LEED’s baseline.Using a high performance glazing system with a custom frit pattern, the terminal achieves optimal thermal performance and mitigates glare. Perforated metal panels on the terminal’s curtain wall filter the low western and eastern sun angles, creating a comfortable day-lit space for waiting customers and responsive daylight controls balance the outdoor and indoor light levels for optimal energy savings. Combined with strategically placed skylights throughout the check-in hall, these will reduce T2’s energy consumption by 23 per cent. The terminal also has a ‘Level 2’ accreditation on carbon management by Airports Council Internationl (ACI). It also boats of a 200,000 sq ft of landscaped garden and is India’s largest airport garden comprising 77,000 plants and over 80 different types of plant species.

Challenges

There were many challenges involved in the construction of T2. GV Sanjay Reddy, Managing Director, GVK Mumbai International Airport Pvt Ltd says, “The biggest challenge that GVK had to overcome was the land constraint at CSIA. The total land area of Mumbai airport was about 2,000 acre. However, a lot of it was occupied and the total land area available for operations was only 1,400 acre. This when compared to land provision for some other airports within and outside India, came across as a significant challenge. The various land challenges were amicably sorted over a period of four years of navigation with various stakeholders.”

Ready for the future

T2 has been constructed at a cost of Rs 5,500 crore, which is the lowest as compared to similar airport projects in India as well as across the globe. It has also constructed a six-lane Elevated Access Road from the Western Express Highway – of 3.2 km length – to the new terminal. This road will cater to 70 per cent of the airport traffic.

Built in four years, the new T2 is an iconic global mega structure and India’s first and most advanced vertical passenger terminal that integrates world-class design, architecture, infrastructure and operational efficiency with a rich infusion of Indian heritage and cultural character.

T2: Incredible Facts

15 m tall cable stayed glass wall – the longest in the world

11 acre long mega roof supported by only 30 columns

1.85 mn sq ft of granite used, can cover 27 football fields

Skylight glass used in 30,000 sq ft, enough to cover Wimbledon’s Centre court six times over.

4 km of LED lighting used to illuminate facade.

Multi-level car parking facility for 5,200 cars – largest in the country.

Structural Steel and Rebar Steel was used to the tune of 26,000 MT and 58,000 MT respectively

Total cement used: Aprroximately1 Lakh tonne

Almost 18,000 workmen were engaged along with another 1,200 staff comprising contractors, sub-contractors, consultants and clients in the development of this mega structure.

“This is a shining example of large infrastructure projects in the PPP mode. T2 will certainly give a boost to other airports under construction and planning. With this, we are planning 50 more airports in Tier-II and Tier-III cities in India.” - Dr Manmohan Singh, Prime Minister of India

“With this, we are planning to upgrade all airports in India.”- Ajit Singh, Minister for Civil Aviation

“Mumbai has its own history of creating iconic transport structures. The first was by sea – the Gateway of India – the second by land – Chhatrapati Shivaji Terminus – and now by air – the T2.”- GV Sanjay Reddy, Managing Director, GVK Mumbai International Airport Pvt Ltd (MIAL)

“The ceiling is primarily constructed from metal panels with a powder coat finish. The entire layout is tailor-made to suit the unique geometry of the terminal.”- Lopa Desai, Local Partner, durlum GmbH

“Inspired by traditional Indian textiles and craft, the Lotus chandeliers, Diya wall and Phulkari lights have been implemented with contemporary fabrication techniques.”- Designers Abu Jani and Sandeep Khosla